DE 199 12 087 A1 discloses a steering column switch, which includes a rotary switch for the front wiper functions arranged rotationally symmetrically on a longitudinal axis of a switch lever of the steering column switch. A push-button switch for a front washer function is arranged at the free end of the switch lever. In addition, another rotary switch for the rear wiper/washer functions is arranged on the rotary switch for the front wiper functions. Both the front wiper functions and the rotary switch for the rear wiper/washer functions have a number of contact bridges that corresponds to the number of switch positions, wherein these contact bridges act on corresponding switch contact tracks. The contact bridges and the associated switch contact tracks are shaped like circular segments at the periphery of a rotary switch element of each rotary switch at one end of the rotary switch element. To activate the front washer function, the associated push-button switch is pushed in, wherein the push button also acts on. associated switch contact tracks by way of a corresponding activation plunger that interacts with a contact bridge. The connection of the switch contact tracks to contacts of the vehicle power supply is performed by means of connection lines, which are attached to connection contacts and which are led through the longitudinal axis of the steering column switch. Here, the number of connection lines corresponds to the number of switch contact tracks. For a predetermined number of switch positions, the outer diameter of the switch lever is essentially dependent on the space requirements of the connection lines, particularly in the region of cable bushings between the first and the second rotary switch, wherein the connection lines must feature a certain cross section and insulation.
Furthermore, a flexible circuit board is known from DE 198 19 088 A1, which includes a carrier film for conductive tracks and is used as a cable tree for electrical contact of a certain arrangement of electrical and/or electronic components. Such flexible circuit boards are increasingly used as replacements for conventional cable trees consisting of round conductors. The individual conductive tracks are electrically insulated from each other and typically have a rectangular cross section. The top sides of the conductive tracks are electrically insulated by means of a coating or a film.
The solved problem of the invention is creating a steering column switch of the initially mentioned type, whose rotary switches are connected to the vehicle power supply with minimal space requirements.
According to the invention, the problem is solved such that
the connection contacts are connected to the contacts of the vehicle power supply by means of a flexible circuit board,
the circuit board has one branch from the connection to the vehicle power supply, wherein this branch divides into two branches, each with a connection, wherein of these two branches, one transitions into another branch with a connection, and
the connection of the second branch is associated with one rotary switch and the connections of the third and fourth branches are associated with the other rotary switch.
Due to these measures, the space requirements for the electrical connection of the two rotary switches to the vehicle power supply are relatively small, since, on the one hand, the flexible circuit board has a thin structure and, on the other hand, the circuit board is divided into several branches for coupling the rotary switch to the vehicle power supply. Furthermore, the flexibility of the circuit board guarantees high functional reliability of the steering column switch. The circuit board deforms in accordance with the movements of the switch lever as well as the movements caused by the individual rotary switches. In addition, the flexible circuit board is relatively easy to mount by means of simple threads through individual components of the switch lever. The individual branches of the circuit board are manufactured through stamped cut-outs of the circuit board film.
The first branch of the circuit board in the flat plane starting from the connection to the vehicle power supply features a first rectilinear region, which transitions by way of an angled section into a second rectilinear region, which is aligned parallel and spatially separated from the first region. The region of the angled section is arranged in the outlet region of the flexible circuit board from the switch lever and, according to corresponding deformation, enables the connection of the connector to the contacts of the vehicle power supply and provides the flexibility required for the pivoting motion of the switch lever.
Advantageously, the second rectilinear region of the first branch splits in a plane above the connection to the vehicle power supply into the second and third branches, which are aligned parallel to each other, wherein the second branch carries the connection at the end and the third branch extends in a straight line outwards over a plane of the connection. Furthermore, the third branch transitions into an angled section running in the direction of the connection of the second branch, in which the connection is arranged. Finally, the third branch transitions in the region of its angled section into the fourth branch, which carries the connection on the end. The course of the individual branches of the circuit board corresponds to a cable tree-like structure and can be realized for the production of the circuit board with minimal material consumption.
In order to be able to implement the connection of the connectors to the associated connection contacts of the switch contact tracks or the contacts of the vehicle power supply relatively easily, the connection for the vehicle power supply, the connection of the second branch, and the connection of the third branch point in the same direction, and the connection of the fourth branch points in the opposite direction.
According to an advantageous refinement of the invention, the connection contacts of the first rotary switch, which is allocated to the free end of the switch lever, are divided into two groups arranged diametrically opposite each other and spatially separated, wherein the first group is connected to the connection of the third branch and the second group is connected to the connection of the fourth branch of the circuit board. Because the connection contacts are provided in two groups, the space requirements for the plurality of connection contacts is extremely small and simultaneously, the functionality of the first rotary switch is guaranteed.
So that the connection between the connection contacts and the contacts of the vehicle power supply by means of the flexible circuit board do not have a disruptive effect on the mechanics of the first rotary switch, the fourth branch of the circuit board in the assembled state of the first rotary switch preferably passes to the side of the hinge pin formed on an intermediate ring.
In a further configuration of the invention, the fourth branch of the circuit board is deformed essentially in the form of a W due to a crosspiece of the intermediate ring supported to the side of the locking sleeves. This deformation is realized automatically during assembly and must be taken into account only for the length dimensioning of the fourth branch.
In order to create a long-lasting electrical connection between the connections and the associated contacts, the connections have contact points that are soldered to the associated connection contacts or to the contacts of the vehicle power supply.
The rotary switch element of the first rotary switch preferably features a contact arm to be activated by a push button inserted in the first rotary switch for acting on associated switch contact tracks. Thus, another switch is integrated in the steering column switch. The electrical connection of this switch to the contacts of the vehicle power supply is realized by means of the flexible circuit board without additional space requirements.
Advantageously, the switch contact tracks of the first and second rotary switch are structured as an extrusion-coated stamped grid, wherein the switch contact tracks of the first rotary switch are arranged on the hinge pin of the intermediate ring and the switch contact tracks of the second rotary switch are arranged on an axial end of an activation element of the rotary switch. The extrusion-coated stamped grids can be handled easily during the soldering of the connections of the circuit board and during the assembly in the switch lever.
It is understood that the features mentioned above and the features still to be explained in the following can be used not only in the indicated combination, but also in other combinations without leaving the scope of the present invention.